The objective of this work was to analyze the relationship between ovine major histocompatibility complex (MHC) DRB1 gene polymorphism and genetic resistance to hydatidosis in Kazakh sheep. The Ovar (ovine MHC) class II DRB1 second exon was amplified by polymerase chain reaction (PCR) from DNA samples of 702 Kazakh sheep, including 302 sheep with hydatidosis and 400 health controls. PCR products were characterized by the restriction fragment length polymorphism (RFLP) technique using five restriction enzymes, i.e., MvaI, HaeIII, SacI, SacII and Hin1I, yielding 14 alleles and 28 genotypes. Comparing the frequency of genotypes in hydatidosis sheep with the control group, it was found that the genotype frequencies of MvaIbc, Hin1Iab, SacIIab, HaeIIIde, HaeIIIdf and HaeIIIdd in control sheep were significantly (p<0.01) higher than in hydatidosis sheep, indicating that a significant correlation existed between these genotypes and resistance to hydatidosis. Genotype frequencies of MvaIbb, SacIIaa, Hin1Ibb and HaeIIIef in sheep with hydatidosis were extremely significantly (p<0.01) higher than in the control group, and the genotype frequency of HaeIIIab was significantly higher (p<0.05), indicating that a marked correlation existed between these genotypes and susceptibility to hydatidosis. By way of analyzing haplotype with these resistant genotypes, the hydatidosis resistant haplotype MvaIbc-SacIIab-Hin1Iab of Kazakh sheep was screened out, and then verified through artificial hydatid infection in sheep. The results indicated that the infection rate of sheep with the resistant haplotype of hydatidosis was significantly lower (p<0.01) than without this resistant haplotype. It showed that the genic haplotype MvaIbc-SacIIab-Hin1Iab of Ovar-DRB1 exon 2 was the resistant haplotype of hydatidosis in Kazakh sheep.

Effect of genetic variation in the MHC Class II DRB region on resistance and susceptibility to Johne’s disease in endangered Indian Jamunapari goats, International Journal of Immunogenetics, 2012, 39, 4, 314

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